alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed Atemu RAT Domain (api .mynetwork .icu in TLS SNI)"; flow:established,to_server; tls.sni; bsize:17; content:"api.mynetwork.icu"; fast_pattern; reference:md5,a3ce0c6600781e0196aad961e92123ed; classtype:domain-c2; sid:2068889; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2026_04_21, deployment Perimeter, malware_family Atemu_RAT, performance_impact Low, confidence High, signature_severity Major, updated_at 2026_04_21, mitre_tactic_id TA0037, mitre_tactic_name Command_And_Control, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)